In modern, western societies like ours, being raised without a father is associated with a host of negative developmental outcomes for children, including substance abuse, aggression and conduct disorder, dropping out of school and risky sexual behavior in adolescence. When fathers are present, however, they are not always helpful, and a small minority are even abusive. On the other hand, children raised by sensitive, nurturing fathers have better cognitive, behavioral, social and psychological outcomes. The proposed project will investigate the neurobiology underlying sensitive fathering and determine whether a pharmacological intervention can enhance it. The first aim is to investigate the relationship between fathers' neural responses to infant picture and cry stimuli and actual behavior of fathers in everyday life as assessed by the Electronic Activated Recorder (EAR), a portable digital audio recorder that periodically records brief snippets of ambient sounds and unobtrusively samples acoustic observations of participants' momentary social environments and interactions within the natural flow of their lives. This aim will use previously collected EAR data from 60 fathers of 1-3 year old children to code several measures of paternal behavior. Measures of paternal behavior will then be correlated with previously collected neuroimaging data from the same fathers. Aim 2 will determine if intranasal OT or AVP alter paternal neural responses to own child picture and cry stimuli. Thirty fathers with 1- 3 year old children will be imaged with fMRI as they view pictures of their own and unknown children and as they listen to unknown infant cry stimuli. Fathers will be scanned on two separate occasions; once under the influence of OT (n=15) or AVP (n=15), and once under the influence of a placebo. Order of administration will be counterbalanced across subjects. Ultimately, it is hoped that interventions like these will improve children's mental and physical health by virtue of their effects on the brain physiology and behavior of at-risk fathers (e.g., abusive fathers, fathers with post-partum depression).